These two RS-232 interface chips feature rugged ESD protection, 3 V to 5.5 V supply voltage, 250-kbit/s minimum data rate, and low-power operation. Of the two RS-232 interface chips, the ST3243E includes three drivers and five receivers, while the ST3232E has two drivers and two receivers. Both chips also include a dual charge-pump circuit. The charge pumps require only four 0.1-μF capacitors. Other key specifications shared by both the ST3243E and ST3232E include a minimum 250-kbits/s data rate at RS-232 levels, 6 V/s slew rate, and as much as a 40°C to +85°C operating temperature range. Chips having a 0°C to 70°C range are also available. To conserve power, the ST3243E includes an auto-powerdown function that cuts supply current consumption to as low as 1 μA. The ST3232E conserves power by limiting supply current to 300 μA. It also features a typical output voltage swing of ± 5.4 V with all lines loaded, a receiver input voltage range of ± 25 V, and a typical propagation delay input to output of 0.15μs.